Established lymphoid cell lines derived from human peripheral blood provide uncommonly useful models for the detailed analysis of lymphoid functions of immunologic significance. Our preliminary studies demonstrate that these cells synthesize in large quantities the potent extracellular mediators of delayed-type hypersensitivity, including a migration inhibitory factor, a cytotoxic factor, a blastogenic factor, a chemotactic factor, interferon and an inhibitor of DNA synthesis. A broad based effort to concentrate, isolate, and characterize these readily accessible products of human lymphoid cell lines utilizing preparative and separative techniques including ultrafiltration column chromatography, and disc electrophoresis is in progress. The purified materials will be analyzed for all their biologic activities with standard and refined in vitro methods available for the detection of the mediators of cellular immunity. These investigations should determine whether the putative mediators of human cell-immune reaction are multiple and distinct or similar molecular species with multiple biologic effects. Collateral study of materials from non-lymphoid cell lines will determine if these "immunologic" factors are exclusive products of lymphoid cells or are produced by activated cells of varied origin and function. With the purified materials we propose to raise specific immunologic reagents to monitor by immunofluorescent and micro- complement fixation techniques the production of these mediators and the sites and mechanisms of their interaction.